GIS-Based Physiochemical and Regression Analysis of Drinking Water Quality in Dhaka South City Corporation, Bangladesh

This study aims to investigate the physio-chemical drinking water quality in the Dhaka South City Corporation (DSCC), Bangladesh, where the Dhaka Water Supply and Sewerage Authority (DWASA) is the major source of drinking water. A total of 22 samples were collected from different outlets of the DWASA water supply chain. The significant physicochemical parameters were assessed using standard test methods. The test result shows that the pH value of all sampling water varied from 6.90 to 7.15. Total solids in the sampling water in ten locations exceeded the permissible limits of WHO standards. The TDS value varies from 160 to 470 mg/L, while the TSS value varies from 116 to 328 mg/L. Except in nine locations, EC of DWASA water was within the permissible limit according to the BD standard. Similar results were observed for temperature, calcium, and chloride; all the locations were within the higher limit. However, twenty sampling locations were critical for Mg hardness, which ranges from 22.21 to 36.94 mg/l. The water in DSCC was also critical for COD; all sample locations exceeded the value of permissible limits. Finally, regression analysis revealed that a strong positive correlation was observed between EC and TDS (R = 0.91), TDS and TS (R = 0.79), and EC and TS (R = 0.72). The analysis reveals the fact that the water supplied by DWASA in the DSCC area needs a degree of treatment before consumption. The proposed spatial distribution maps might be very helpful for the policymaker as an indicator for safe and unsafe drinking water outlets in the specified area.